A Reddit user has found an encrypted message written in a dictionary. Can a reader break this cryptogram?

First of all, I wish all my readers a Happy New Year 2018!


The dictionary cryptogram

My first blog article in 2018 is about an unsolved ciphertext that was posted on Reddit a few weeks ago. Here it is:


Reddit user RonnieMays published this cryptogram last November in the /r/codes forum. It is written as a dedication in a Chinese dictionary. The text doesn’t look Asian to me. My guess is that it is a message in a European language (English?) encrypted in a monoalphabetic substitution cipher (MASC). Here’s a transcription posted by another Reddit user:




The dictionary crptogram, as I will call this ciphertext, consists of 75 letters. Here’s a frequency analysis made with CrypTool 2:


In my view, these freqeuncies are consistent with a MASC applied on an English plaintext. The Index of Coincidence (i.e., the probability that two randomly drawn letters are equal) is 4.8 percent. This is considerably lower than the Index of Coincidence of an ordinary English text (6.7 percent). This difference might be due to abbreviations the author used or some similar effect.

It is, of course, also possible that this message was written in a different language than English. Here are few Index of Coincidence values of common languages (source: dCode):

  • English: 6.7 percent
  • French: 7.8 percent
  • German: 7.6 percent
  • Spanish: 7.7 percent
  • Italian: 7.4 percent
  • Russian: 5.3 percent

Do the most frequent letters in the ciphertext (B and I) stand for E and T? If so, we can substitute a few letters in the cryptogram:

aEcde fgh TEcdT ,
jud TEk lmeT jEckE
neaop TEqrs rkgtEf vw(c?)
fwTsET dkdeT, jud gx hEq(g?)
kgT sdE.

This interim status doesn’t look very promising, as the expressions TEcdT and TEk don’t decrypt to common English words. If we switch the meanings of E and T (i.e., B=T, E=E), it doesn’t get better, as expressions like TEcdE or ETk don’t make much sense.

As far as I see, the dictionary crptogram doesn’t contain a word with a letter pattern that is unusual enough to be identified.

Apparently, this cryptogram is a little more difficult than it looks like at first view. Can a reader break it anyway?

Further reading: Who can solve this encrypted diary entry?


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Kommentare (5)

  1. #1 Gerry and Andrea
    1. Januar 2018

    There are some transcription errors (last word in line 1 and second word in line 4, assuming the comma is not a character):
    KGI SDB.

  2. #2 J.K. Petersen
    17. Januar 2018

    Hello, Klaus. I am finally taking a look at your blog!

    This one caught my eye because some of the glyph shapes, and the way the pen moves, look to me like they might have been written by a person familiar with Hiragana.

    I know a little bit of Japanese but not enough to read it if it is written in cipher text.

    Even if the shapes were written by someone who knows Hiragana, it doesn’t necessarily mean the underlying text is Japanese, of course… it could be many other languages.

  3. #3 J.K. Petersen
    17. Januar 2018

    I should give an example… this isn’t actually a decryption, simply a structural observation that jumped out at me when I first glanced at it, that the first line could read something like “Kanji _ _ _ kana _ with “tee” being the letter “a” and “leee” being the letter “i”, etc. (a substitution code).

    Other consonants are possible, short words don’t provide much context, but I think there’s a good chance tee and leee are vowels.

  4. #4 J.K. Petersen
    17. Januar 2018

    If it is an Asian language, then each symbol is potentially a syllable.

    In Hiragana, for example, individual characters represent syllables such as wa, ra, ro, yo, ki, ka, etc. Some of these are constructed from shapes that are similar to the glyph at the end of the first word in the fifth line. The ladder-like symbol used twice in the third line resembles the Hiragana characters “ma” or “ki” without the bottom loop or “ki” in Katakana (Katakana is traditionally used to represent foreign words).

    Even that lone apostrophe-shape has an Asian feel to it. A number of katakana characters add ticks or small loops to the main shape.

    The bowl-shape with the three dots above it is like the Urdu syllable “se”. If the person who wrote this was choosing shapes that are common to syllabic languages, then the cipher characters may also represent full syllables.

  5. #5 Charlotte Auer
    17. Januar 2018

    Um sich mit einer derartigen “Geheimschrift” länger als eine Stunde ernsthaft oder auch nur spaßeshalber zu befassen, sind wohl mehr Informationen nötig, als ein dürftiger Hinweis wie “as a dedication in a Chinese dictionary”.

    Welches “Chinese dictionary”, wann und wo erschienen, Original oder Reprint, ist die Widmung original, gibt es andere Scans vom Buch ? Usw. usw. Sich sowas zusammen zu basteln und ohne jeglichen nachprüfbaren Kontext online zu stellen, ist ja nun wirklich kein Kunststück. Es darf also auch sehr bezweifelt werden.

    Die Schrift selber enthält aus meiner Sicht Elemente aus verschiedenen Alphabeten verschiedener Epochen, die auf den ersten Blick so in Richtung Aramäisch-Glagolitisch-Georgisch u.ä. gehen und ziemlich wild gemixt und teilweise einfach selbst erfunden aussehen. Insbesondere die Initiale lässt da gewisse Schlüsse zu. Eine ostasiatische Herkunft ist alleine schon von der Schreibrichtung und Anordnung eigentlich auszuschließen.

    Solange ich diese “Widmung” nicht in einem nachvollziehbaren originalen Kontext sehen kann, halte ich sie für einen Hoax, für den ich keine Zeit verschwenden werde.

    Sorry Klaus, wenn ich das so unverblümt sage, aber etwas derartiges einfach ungeprüft aus dem Netz zu übernehmen und nicht grundsätzlich zu hinterfragen, halte ich für keine besonders gute Idee. Jedenfalls für keine, die dem Niveau Ihres Blogs angemessen wäre. Da gibt es hier ja wirklich wesentlich bessere Kryptorätsel, für die sich die Zeit auch lohnt und die ja nicht selten zu genialen Lösungen führen.